The NIDDK conducts and supports much of the clinical research on the diseases of internal medicine and related subspecialty fields. Many of the large clinical studies funded by the NIDDK collect biospecimens from subjects for analysis and future study. The collection of these patient and control samples from many different studies in a single repository is a valuable resource with which researchers can rapidly validate clinical hypotheses and algorithms for clinical decision. The collection is also advancing the development of prognostics, markers, and therapeutics for diseases related to the mission of the NIDDK. This project, which will be referred to herein as ?the Biosample Repository?, continues an important collection begun in 2003 and is conceptually related to repositories in existence at other institutes at the NIH.